Free surface flow over a trapezoidal cavity with surface tension effect
Abstract
This paper investigates two-dimensional free surface flows over a trapezoidal cavity in a fluid with finite depth. By assuming that the flow is steady, irrotational, and that the fluid is non-viscous and incompressible. We suppose that the surface tension is included in the nonlinear boundary condition derived from Bernoulli’s equation. A numerical approach using the series truncation method is employed to solve the problem. Solutions are computed for a symmetric trapezoidal obstacle for each value of the Weber number and the height of obstacle. The influence of the Weber number, the bottom height, and the angle of the obstacle are discussed.
Copyright (c) 2025 Author(s)

This work is licensed under a Creative Commons Attribution 4.0 International License.
References
[1]Hanna SN, Abdel-Malek MN, Abd-el-Malek MB. Super-critical free-surface flow over a trapezoidal obstacle. Journal of Computational and Applied Mathematics. 1996; 66: 279–291.
[2]Dias F, Vanden-Broeck JM. Open channel flows with submerged obstructions. Journal of Fluid Mechanics. 1989; 206: 155–170.
[3]Sekhri H, Guechi F, Mekias H. A waveless free surface flows past a submerged triangular in presence of surface tension. Electronic Journal of Differential Equations. 2016; 2016(190): 1–8.
[4]Abd-el-Malek MB, Hanna SN, Kamel MT. Approximate solution of gravity flow from a uniform channel over triangular bottom for large Froude number. Applied Mathematical Modelling. 1991; 15: 25–32.
[5]King AC, Bloor MIG. Free surface flow over a step. Journal of Fluid Mechanics. 1987; 182: 193–208.
[6]King AC, Bloor MIG. Free streamline flow over curved topography. Quarterly of Applied Mathematics. 1990; 48: 281–293.
[7]Laiadi A, Merzougui A. Free surface flows over a successive obstacles with surface tension and gravity effects. AIMS Mathematics. 2019; 4: 316–326.
[8]Mansoor WF, Hocking GC, Farrow DE. Unsteady free surface flow due to a line sink at an arbitrary location with surface tension. Computers and fluids. 2023; 266.
[9]McLean E, Robert Bowles, Vanden-Broeck JM. Wake flow past a submerged plate near a free surface. European Journal of Applied Mathematics. 2024; 1–14.
[10]Birkhoff G, Zarantonello EH. Jets, Wakes and Cavities. Academic Press; 1957.
[11]Asavanant J, Vanden-Broeck JM. Non-linear free surface flows emerging from vessels and flows under a sluice gate. J. Austral. Math. Soc. Ser. B. 2009; 38: 63–86.
[12]Tuck EO, Vanden-Broeck JM. Ploughing flows. European Journal of Applied Mathematics. 1998; 9: 463–483.
[13]Laiadi A. The influence of surface tension and gravity on cavitating flow past an inclined plate in a channel. Quarterly of Applied Mathematics. 2022; 80(3): 529–548.
[14]Vanden-Broeck JM. Gravity-capillary free surface flows. Cambridge University Press; 2010.
[15]Vanden-Broeck JM, Tuck EO. Flow Near the Intersection of a Free Surface with a Vertical Wall. SIAM Journal on Applied Mathematics. 1994; 54(1): 1–13.
[16]Chedala FZ, Amara A, Meflah M. Numerical and analytical calculations of the free surface flow between two semi-infinite straights. Journal of Applied Mathematics and Computational Mechanics. 2020; 19(4): 21–32.
[17]Doak A, Vanden-Broeck JM. Nonlinear two-dimensional free surface solutions of flow exiting a pipe and impacting a wedge. Journal of Engineering Mathematics. 2021; 126: 1–19.



